Analysis of powertrain design on effective waste heat recovery from conventional and hybrid electric vehicles

Fuel energy distribution in the ICE is used to evaluate the sources of waste heat and identify exhaust energy recovery as the most promising method for improving ICE thermal efficiency. Fundamental analysis of conventional and hybrid powertrain design is used to investigate how they impact the availability of exhaust energy from the ICE. Models and simulations of several engines and vehicles are used to validate the theory presented for effective WHR from light-duty vehicles. The analysis focuses on how available exhaust energy changes for different vehicles, how it varies with drive cycles, and how the induced back pressure from an exhaust energy recovery system affects ICE performance. The results indicate that effective WHR is difficult to achieve in light-duty conventional vehicles, but is viable in a highly hybridized vehicles, where ICE thermal efficiency can be increased by at least 15 percent over various drive cycles.